The present invention relates to a server system, client system, and difference update system which update differences between a server and clients which share information in real-time.
When a computer is connected to a network such as the Internet to browse the contents and the like of a Web sever constructed on the network through the computer, software called a Web browser is used. The Web browser allows a user to browse contents prepared in a Web server using, for example, HTTP (Hyper Text Transfer Protocol).
The contents acquired from a Web sever into a local computer with HTTP and browsed with the Web browser are generally updated by inputting an update instruction to the Web browser. In addition, the contents are automatically updated by the automatic updating function of the Web browser which is activated at predetermined intervals. Conventionally, updating of information in a browser is automatically executed in a pseudo-fashion by automatic updating performed at predetermined intervals by update button operation of the browser. Therefore, real-time communication between a server and a client is performed by installing software dedicated to HTML or downloading a JAVA program having a large size every time it is used, without using the browser.
In a conventional system, a dedicated program must be downloaded from a server into a client. Since this operation takes time, it takes time to allow updating of a content to be changed. For this reason, a change in content on the server side cannot be quickly reflected in the corresponding information on the client side. This makes it impossible to maintain consistency of information. In addition, in the conventional system, as described above, since a dedicated program is used, a high development cost is required for such a program. Furthermore, a dedicated program to be prepared for each HTML provided must be prepared on the client side for each HTML with which the user browses. This requires the user to perform complicated operation.